Legal Question in Real Estate Law in Illinois

Depends whether there was a contract between the parties. In Illinois all contracts for sale of real estate must be in writing (may e proven by various ways including emails). Otherwise, insufficient information.

A better recitation of the background would be helpful. If the seller is not living up to the contractual obligations, then you may be able to take certain steps against the seller, individually or against the property. Unlikely that this is something you can accomplish without counsel.